Optical energy-based methods and apparatus for tissue sealing

ABSTRACT

Optical energy-based methods and apparatus for sealing vascular tissue involves deforming vascular tissue to bring different layers of the vascular tissue into contact each other and illuminating the vascular tissue with a light beam having at least one portion of its spectrum overlapping with the absorption spectrum of the vascular tissue. The apparatus may include two deforming members configured to deform the vascular tissue placed between the deforming members. The apparatus may also include an optical system that has a light source configured to generate light, a light distribution element configured to distribute the light across the vascular tissue, and a light guide configured to guide the light from the light source to the light distribution element. The apparatus may further include a cutting member configured to cut the vascular tissue and to illuminate the vascular tissue with light to seal at least one cut surface of the vascular tissue.

BACKGROUND

1. Technical Field

The present disclosure is directed to tissue sealing and, in particular,to systems and methods for tissue sealing employing optical energy.

2. Background of Related Art

Existing energy-based surgical systems and methods use electrical energyor ultrasound energy to heat tissue (see, e.g., U.S. Pat. Nos. 7,384,420and 7,255,697, and U.S. Patent Application Publication Nos. 2008/0147106and 2009/0036912). For example, electrosurgical systems include anelectrosurgical generator for producing high frequency electrical energy(e.g., radio frequency (RF) or microwave (MW) energy) and anelectrosurgical instrument for applying the electrical energy to tissue.A surgeon may use the electrosurgical instrument to cut, coagulate,desiccate, and seal tissue.

Existing energy-based surgical methods and systems, however, may haveseveral disadvantages that limit their performance and effectiveness.First, they may limit the surgeon's ability to control and localizeenergy in tissue. As a result, the energy thermally damages tissueadjacent to the target tissue. Also, energy is lost because an excessivevolume of tissue is heated (i.e., both the target tissue and theadjacent tissue are heated).

Second, existing energy-based devices require direct physical contactbetween the tissue and the electrodes, ultrasound transducers, orsound-conducting portions of the surgical instrument to transmit energyto the tissue. As a result, a significant amount of energy is lost tothe environment and to that portion of the instrument in contact withthe heated tissue, while only a small amount of energy is used toactually heat tissue. Also, tissue may attach to that portion of theenergy-based instrument that is in contact with the tissue.

Third, existing energy-based instruments may obstruct the surgeon's viewof the target tissue or the operating site. Fourth, existingenergy-based instruments typically include a large generator and asignificant amount of wiring.

Lastly, electromagnetic energy-based systems and methods (e.g., RF- andMW-energy-based systems and methods) may cause stray currents,flashovers (e.g., an electric arc between the instrument and thetissue), short circuits in the conducting enviromnent, and/orelectromagnetic interference with other tissues and devices.

There are a number of laser-based surgical instruments, such as laserscalpels, that use laser radiation to cut and coagulate tissue. Onedisadvantage of laser scalpels is that they cannot seal relatively largevessels because laser scalpels cannot bring together opposite walls ofthe vessels. For example, in the article, Rodney A. White, et al.,“Large vessel sealing with the argon laser,” Lasers in Surgery andMedicine 7, pages 229-235 (1987), the edges of damaged vessels are firstapproached to each other and then sealed by exposing them to laserradiation.

There are also devices that use light to perform tissue ablationprocedures. For example, as described in U.S. Pat. No. 4,266,547, tissueis placed between transparent holders through which the light isintroduced to the tissue. The absorption of light by the tissue causesheating, charring, and ablation of the tissue. In optical ablation, thetissue can be illuminated with propagating waves or evanescent wavesresulting from total external reflection. See, e.g., Cox, et al., “Newmethod for exposing mammalian cells to intense laser radiation using theevanescent fields created in optical waveguides,” Med. Phys. 5:274-279(1978).

There are also instruments for coagulating blood vessels through theskin without deforming or damaging the tissue. For example, U.S. Pat.No. 7,452,355 describes simultaneously using multiple wavelengths oflight radiation so that the radiation of one of the wavelengths modifiesthe blood and creates in the blood centers of high absorption of theradiation of other wavelengths, which can penetrate deeper into thetissue and completely seal the vessel.

The optical methods and systems described above, however, may notprovide high quality vascular tissue sealing, especially for relativelylarge vessels.

SUMMARY

The surgical systems and methods according to embodiments of the presentdisclosure provide efficient sealing of vascular tissue including largevessels and mitigate the disadvantages of existing methods and devices,which are based on RF current, ultrasound, or optical radiation.

In one aspect, the present disclosure features method of sealingvascular tissue. The method includes deforming vascular tissue to causedifferent layers of the vascular tissue to contact each other andilluminating at least one portion of the vascular tissue with lighthaving at least one portion of the light's spectrum overlapping with anabsorption spectrum of the vascular tissue. The light may include atleast a first light wave having a first wavelength and a second lightwave having a second, different wavelength. The first light wave maychange the optical parameters of the vascular tissue or a. component ofblood within the vascular tissue to increase the absorption of thesecond light wave by the vascular tissue or the component of bloodwithin the vascular tissue.

In some embodiments, the method further includes forming the light intoat least one light beam. In other embodiments, the method furtherincludes forming the light into at least two light beams that propagateat different angles with respect to the deformed vascular tissue.

In some embodiments, the light may be configured to penetrate thevascular tissue through a surface of the vascular tissue whilemaintaining the original integrity of the surface of the vasculartissue. In other embodiments, the light may be configured to penetratethe vascular tissue through a cut in the vascular tissue formed prior toor during sealing of the vascular tissue.

In some embodiments, illuminating the at least one portion of thevascular tissue with light includes illuminating the at least oneportion of the vascular tissue with light all at one time. In otherembodiments, illuminating the at least one portion of the vasculartissue with light includes forming the light into at least one lightspot and scanning the at least one light spot over the at least oneportion of the vascular tissue.

The method may further include monitoring at least one parameter of thevascular tissue and controlling at least one parameter of the lightbased on the at least one parameter of the vascular tissue. The at leastone parameter of the light may include one or more of intensity,frequency, polarization, phase, pulse width, pulse frequency, dutycycle, repetition rate, wave shape, duration of illumination, totalexposure of tissue to the light, or the spectra of the light. Also, theat least one parameter of the vascular tissue may include one or more ofthe electrical impedance of a volume of the vascular tissue, the opticaltransparency of the vascular tissue, the degree of optical anisotropy ofthe vascular tissue, or the polarization-dependent optical loss in thevascular tissue. In some embodiments, the method may further includesensing the temperature of the vascular tissue and controlling at leastone parameter of the light based on the temperature of the vasculartissue.

In some embodiments, deforming the vascular tissue includes stretchingthe vascular tissue along a longitudinal axis of a vessel within thevascular tissue. In other embodiments, deforming the vascular tissueincludes compressing the vascular tissue.

In another aspect, the present disclosure features an energy-basedinstrument for sealing vascular tissue. The energy-based instrumentincludes a deforming member for deforming vascular tissue and an opticalsystem for illuminating a portion of the vascular tissue with light toseal the vascular tissue. The optical system includes a light source forgenerating light, a light distribution element for distributing thelight over the portion of the vascular tissue, and a light guide forguiding the light from the light source to the light distributionelement.

The deforming member of the energy-based instrument may include at leasta first deforming member and a second deforming member for moving inopposite directions and for deforming vascular tissue placed between thefirst deforming member and the second deforming member. At least one ofthe first deforming member and the second deforming member may includeoptical reflective material for reflecting the light and for causing thelight to pass through the vascular tissue at least twice. Also, at leastone portion of at least one of the first deforming member and the seconddeforming member may be transparent to the light.

In some embodiments, a portion of at least one of the first deformingmember and the second deforming member does not contact the portion ofthe deformed vascular tissue that is illuminated with the light. Thelight distribution element may be optically coupled to at least one ofthe first deforming member and the second deforming member.

The energy-based instrument may further include a sensor for sensing atleast one parameter of the vascular tissue and a controller forcontrolling at least one parameter of the light generated by the lightsource based on the at least one parameter of the vascular tissue sensedby the sensor. The at least one parameter of the light may include oneor more of intensity, frequency, polarization, phase, pulse width, pulsefrequency, duty cycle, repetition rate, wave shape, duration ofillumination, total exposure of tissue to the light, or the spectra ofthe light.

The light source of the energy-based instrument may include at least onelight emitting diode or at least one laser. The at least one laser maygenerate light having different wavelengths. Also, the at least onelaser may be a tunable laser that is tuned to generate light of adesired wavelength.

The light distribution element of the energy-based instrument may beconfigured to create conditions of frustrated total internal reflection.The light distribution element may include at least one lens, at leastone prism, at least one waveguide structure, or at least one periodicoptical structure. The at least one periodic optical structure may be adiffraction grating, such as a Bra diffraction grating. In someembodiments, the light guide includes at least one waveguide structure,such as an optical fiber.

In yet another aspect, the present disclosure features an energy-basedinstrument for cutting and sealing vascular sue. The energy-basedinstrument includes a deforming member for deforming vascular tissue tocause different layers of the vascular tissue to contact each other anda cutting member for cutting the vascular tissue and illuminating atleast one portion of the vascular tissue with light to seal at least onecut surface of the vascular tissue.

The deforming member may include a first deforming member and a seconddeforming member configured to move in opposite directions and to deformvascular tissue placed between the first deforming member and the seconddeforming member. The cutting member may be a movable cutting member andat least one of the first deforming member and the second deformingmember may include a recess to guide the moveable cutting member to cutthe vascular tissue.

The energy-based instrument may further include a light source forgenerating light. The cutting member may include an optical beam formercoupled to the light source. The optical beam former may form the lightinto a light beam to cut the vascular tissue. In other embodiments, thecutting member includes a cutting edge that mechanically cuts thevascular tissue.

The cutting member may include an optical waveguide for guiding lightthrough at least one side of the cutting member and illuminating thevascular tissue with the light to seal the at least one cut surface ofthe vascular tissue. The optical waveguide may be configured to createconditions of frustrated total internal reflection on at least one sideof the optical waveguide.

The optical waveguide may include a light distribution element fordistributing light on at least one cut surface of the vascular tissuethrough at least one side of the optical waveguide. The lightdistribution element may include at least one periodic opticalstructure.

In yet another aspect, the present disclosure features a method ofcutting vascular tissue. The method includes deforming vascular tissueto cause different layers of the vascular tissue to contact each other,cutting the deformed vascular tissue, and illuminating the deformedvascular tissue with light to seal at least one cut surface of thevascular tissue.

The method may further include generating light sufficient to cut thedeformed vascular tissue, forming the light into a light beam, andapplying the light beam to the vascular tissue to cut the deformedvascular tissue.

In some embodiments, cutting the deformed vascular tissue includesapplying mechanical force to a cutting member to cut the deformedvascular tissue. In other embodiments, cutting the deformed vasculartissue includes cutting the deformed vascular tissue with a cuttingmember and illuminating the deformed vascular tissue with light includesforming a light beam within a cutting member and illuminating thedeformed vascular tissue with the light be through at least one side ofthe cutting member. The step of illuminating the deformed vasculartissue with light may include creating conditions of frustrated totalinternal reflection on at least one side of an optical waveguide withinthe cutting member.

In some embodiments, deforming the vascular tissue includes stretchingthe vascular tissue along a longitudinal axis of a vessel within thevascular tissue. In other embodiments, deforming the vascular tissueincludes compressing the vascular tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments will be described herein below with reference to thedrawings wherein:

FIG. 1 is a block diagram of an optical sealing system according toembodiments of the present disclosure;

FIG. 2 is an illustration of a method of sealing vascular tissueaccording to embodiments of the present disclosure;

FIG. 3 is a cross-sectional side view of a portion of an instrumentsused to seal vascular tissue according to some embodiments of thepresent disclosure;

FIG. 4 is a cross-sectional side view of a portion of an instrument usedto seal vascular tissue according to other embodiments of the presentdisclosure;

FIG. 5 is a cross-sectional front view of the instrument of FIG. 4;

FIG. 6 is a perspective view of a cutting member according to yet otherembodiments of the present disclosure;

FIG. 7 is a cross-sectional front view of the cutting member of FIG. 6in an instrument used to seal and cut vascular tissue according tocertain embodiments of the present disclosure; and

FIG. 8 is a flow diagram of a method of sealing vascular tissueaccording to some embodiments of the present disclosure.

DETAILED DESCRIPTION

As described above, existing methods of heating and sealing vasculartissue (e.g., vessels) using electromagnetic radiation in the radiofrequency (RF) range may have some drawbacks. These drawbacks mayinclude stray currents, flashover, short circuits, the need forelectrical insulation, and interference with other tissues, organs, andmedical devices. Using light to heat and seal vascular tissue avoidsthese drawbacks while also maintaining the integrity of the tissue. Theterm “light” as used in the present disclosure refers to electromagneticradiation in the infrared, visible, and ultraviolet regions of theelectromagnetic spectrum.

According to embodiments of the present disclosure, tissue sealing isaccomplished by deforming the vascular tissue to provide direct contactbetween different layers of the vascular tissue and illuminating thevascular tissue with light. Absorption of the light by the tissue causesthe heating of the vascular tissue followed by the melting ordenaturizing of the collagen and elastin in the vascular tissue.Deforming the vascular tissue through mechanical impact facilitates therelease and mixture of collagen and elastin from the vascular tissue.When the light is removed from the vascular tissue, the melted collagenand elastin reform to create a permanent vascular tissue seal.

FIG. 1 is a block diagram of a vascular tissue sealing system 100according to embodiments of the present disclosure. The system 100includes a light source 120, a light guide 110, a light distributionelement 111, and a deforming member 121, which operate together to forma high-quality tissue seal. The deforming member 121. applies a force102 to deform the vascular tissue 101 and bring different layers of thevascular tissue 101 into direct physical contact with each other. Then,the light source 120 generates light 103 and provides it to the lightdistribution element 111 via the light guide 110. The light distributionelement 111, which may be incorporated into the deforming member 121,forms the light 103 into a light beam 104 and illuminates the vasculartissue 101 with the light beam 104. The light beam 104 heats thedeformed vascular tissue 101 to create a tissue seal.

The vascular tissue sealing system 100 also includes a control systemthat incorporates feedback to control the tissue sealing process. Thecontrol system may use the feedback to optimize the tissue sealingprocess, e.g., to determine optimal exposure, to minimize thermaldamage, and to reduce energy consumption. For example, the controlsystem may use the feedback to adjust amplitude-time characteristics ofthe light 103 (e.g., amplitude, number of pulses, pulse duration, andpulse repetition rate) to obtain a desired tissue seal quality and toavoid tissue charring or destruction.

The feedback may include on one or more optical, electrical, or otherparameter of the vascular tissue. For example, the feedback may includeelectrical impedance, optical transparency, opticalpolarization-dependent loss, or temperature of the vascular tissue. Thefeedback may also include one or more parameters of the electrical,optical, and mechanical subsystems of the vascular tissue sealing system100. For example, the feedback may include the gap distance betweenopposing sealing surfaces of the jaw members 306, 307 (as shown in FIGS.3 and 4) and the pressure applied to the vascular tissue 101. Theseparameters should be accurately controlled to assure a consistent andreliable seal.

The control system of the vascular tissue sealing system 100 may includesensors 112, an analog-to-digital converter (ADC) 113, a controller 114,a user interface 116, and a power supply 118. The sensors 112 sense oneor more optical, electrical, or other parameters of the vascular tissue101 and transmit sensor information in the form of analog sensor signalsto the ADC 113. For example, the sensors 112 may sense opticalparameters of the tissue 101 including the optical transparency of thetissue 101, the degree of reflection from the tissue 101, the opticalloss resulting from absorption and/or scattering by the tissue 101(e.g., the optical polarization-dependent losses in the tissue 101), thedegree of anisotropy of the optical parameters, or any combination ofthese optical parameters as disclosed in commonly-owned U.S. patentapplication Ser. No. ______, entitled “System and Method forEnergy-Based Sealing of Tissue with Optical Feedback,” the entirecontents of which are incorporated by reference herein. In someembodiments, the sensors 112 may include an optical sensor system asdisclosed in commonly-owned U.S. patent application Ser. No. 12/757,340,entitled “Optical Hydrology Arrays and System and Method for MonitoringWater Displacement During Treatment of Patient Tissue,” the entirecontents of which are incorporated by reference herein. The sensors 112may also sense one or more parameters of the light beam 104.

The ADC 113 converts the analog sensor signals to digital sensor dataand transmits the digital sensor data to the controller 114. Thecontroller 114 processes the digital sensor data and regulates one ormore parameters of the light 103 by transmitting appropriate controlsignals to the light source 120. In some embodiments, the ADC 113 isincorporated into the controller 114 and the sensors 112 transmit theanalog sensor signals to the controller 114 via a wirelesscommunications link.

The user interface 116, which may be local to or remote from, thecontroller 114, is coupled to the controller 114 via a communicationslink to allow the user to control various parameters of the light beam104 applied to the vascular tissue 101 during a sealing procedure. Theuser may manually set one or more parameters of the light 103 and/or thelight beam 104 and the controller 114 may regulate and/or control theseparameters. The one or more parameters of the light 103 and/or the lightbeam 104 may include intensity, frequency, polarization, phase, pulsewidth, pulse frequency, duty cycle, repetition rate, wave shape,duration of illumination, total exposure of tissue to the light beam104, or the spectra of the light 103 and/or the light beam 104. Theintensity of the light 103 and/or the light beam 104 may include totalintensity and/or spatial distribution of intensity over the illuminatedtissue. A user may enter data into the user interface 116 such as thetype of instrument, the type of surgical procedure, and/or the tissuetype.

The controller 114 is also coupled to the power supply 118 (e.g., a DCpower supply) via a communications link to enable the controller 114 tocontrol and monitor the power supplied by the power supply 118 to thelight source 120. The controller 114 may receive feedback signals fromthe power supply 118, may generate control signals based on the feedbacksignals, and may transmit these control signals to the power supply 118.The control signals may control the magnitude of the voltage and currentoutput from the power supply 118. The control signals may also beconverted to analog signals by a digital-to-analog converter (DAC) (notshown) before they are applied to the power supply 118.

The controller 114 may include at least one microprocessor capable ofexecuting software instructions for processing data received from theuser interface 116 and the sensors 112 and for outputting appropriatecontrol signals to the light source 120 and/or the power supply 118. Thesoftware instructions executed by the at least one microprocessor may bestored in an internal memory of the controller 114, an internal orexternal memory bank accessible by the controller 114, and/or anexternal memory, e.g., an external hard drive, floppy diskette, orCD-ROM.

The system 100 may be implemented as a single surgical device, such as aportable surgical device, or a surgical device broken up into separatecomponents. For example, the system 100 may include two components: (1)a controller console, which may include the ADC 113, controller 114,user interface 116, and power supply 118, and (2) an instrument, whichmay include the light source 120, light guide 110, deforming member 121,and sensors 112.

FIG. 2 is an illustration 200 showing a method of sealing vasculartissue 101 in accordance with embodiments of the present disclosure. Themethod involves deforming the vascular tissue 101 and exposing at leasta portion of the deformed tissue to a light beam 104. Deforming thevascular tissue 101 brings different layers of the vascular tissue 101,including opposite walls of a vessel 205, into direct contact with eachother. Also, deforming the vascular tissue 101 partially destroys layersof the vascular tissue 101 to facilitate extraction of collagen andelastin from the interlayer space. Finally, deforming the vasculartissue 101 displaces blood or other biological fluids and reduces thevolume of vascular tissue to be sealed.

The vascular tissue 101 may be deformed by compressing the vasculartissue 101, e.g., by applying mechanical force to opposite sides of thevascular tissue 101 as indicated by the arrows 202. Alternatively or inaddition to compressing the vascular tissue 101, the vascular tissue 101may be deformed by extending or stretching the vascular tissue 101 in adirection perpendicular to an axis 206, which is perpendicular to thesurface of the vascular tissue 101. For example, the vascular tissue 101may be deformed by pulling a first portion of the vascular tissue 101 ina first direction 203 a while pulling a second portion of the vasculartissue 101 in a second direction 203 b (i.e., in the oppositedirection). The vascular tissue 101 may also he deformed by twisting thevascular tissue 101 or by applying pressure at different locations onthe vascular tissue 101.

As illustrated, in FIG. 2, the light beam 104 illuminates the vasculartissue 101 at an incidence angle θ 208 with respect to the axis 206. Thelight beam 104 includes at least one spectral component that is withinthe range of the absorption spectra of the tissue so that the light beam104 can heat and seal the vascular tissue 101. The incidence angle θ 208of the light beam 104 may be variable to allow for adjustment of thelight penetration depth and other optical parameters. For example,increasing the angle θ 208 of the light beam 104 decreases the amount oflight energy absorbed by the vascular tissue 101. To vary the angle θ208 of the light beam 104, the system 100 of FIG. 1 may include a lightdistribution element 111 configured to adjust the angle θ 208 of thelight beam 104 in response to appropriate control signals from thecontroller 114.

In some embodiments, the light distribution element 111 and thedeforming member 121 of FIG. 1 are configured to create conditions offrustrated total internal reflection. To create these conditions, therefractive index of the ambient medium 209 (e.g., air) is selected to beless than the refractive index of the vascular tissue 101. Also, thelight distribution element 111 directs the light beam 104 at an anglewith respect to an axis normal to the surface of the deforming member121. The angle may be selected to create total internal reflectionwithin the deforming member 121. In other words, the angle is selectedto cause the entire light beam 104 to reflect off of the boundarybetween the deforming member 121 and the ambient medium 209. When thedeforming member 121 gets close enough to the vascular tissue 101, thereis a transition to frustrated total internal reflection in which thelight beam 104 passes energy from the deforming member 121 across the eambient medium 209 to the vascular tissue 101. This configuration mayreduce the light penetration depth and thus increase the localization ofinduced heating of the vascular tissue 101.

The light beam 104 may be spatially distributed in a manner thatprovides an appropriate distribution of absorbed light energy in thetissue to be sealed. The entire target tissue volume may be exposed tolight all at once or it may be scanned with a light spot or multiplelight spots. In the ease of scanning, less light power may be needed andthe parameters of the light may be adjusted to the local parameters ofthe vascular tissue 101, thus reducing thermal damage. Spatiallylocalized exposure may also be used to provide a sealing mode similar tospot welding. In this case, the tissue is sealed locally in a number ofdiscrete spots.

To more efficiently heat the vascular tissue 191, the light beam 104 mayhave several different wavelengths. The wavelengths can be selected sothat light at one of the wavelengths is absorbed by hemoglobin or otherblood components, which causes the hemoglobin or other blood componentsto absorb light at other wavelengths, which have low absorption bytissue in its initial state prior to illumination.

The use of different wavelengths of light also enables selective heatingof different tissues. For example, tissue containing fat and bloodvessels may be exposed to green light and near-infrared (IR) light. Fathas a low absorption of green light, whereas blood vessels have a highabsorption of green light and thus heat up when illuminated by greenlight. The heating of the blood vessels by the green light causes thecoagulation of hemoglobin and creates an absorption center for near IRradiation. As the coagulated hemoglobin absorbs the near IR radiation,it increases in temperature and heats the blood vessels.

The light may also include at least two light beams that illuminate thevascular tissue at different angles. For example, as shown in FIG. 2, asecond light beam 204 may illuminate the vascular tissue 101 at an angleφ 207 with respect to the axis 206.

As described above, an apparatus or instrument for vascular tissuesealing according to embodiments of the present disclosure includes bothcomponents that deform vascular tissue and components that expose thevascular tissue to light. In some embodiments, the instrument includesat least two members by which force is applied to the vascular tissue togrip, hold, and deform the vascular tissue (e.g., blood vessels or bileducts) to bring different layers of the vascular tissue into contactwith each other.

FIG. 3 shows an embodiment of an instrument having two jaw members 306,307 (i.e., two deforming members). The jaw members 306, 307 areconfigured to move with respect to each other (e.g., the upper jawmember 306 may move while the lower jaw member 207 remains stationary)and to directly contact the vascular tissue 101. The jaw members 306,307 can grasp, hold, and compress the vascular tissue 101 to bringdifferent layers of the vascular tissue 101 into direct contact witheach other, to partially destroy layers of the vascular tissue 101, andto stop the flow of fluid in a vessel (e.g., the vessel 205 of FIG. 2).

The bottom jaw member 307 is made of a material that is at least partlytransparent to the light beam 104 to allow the light beam 104 to passthrough a portion of the jaw member 307 to the vascular tissue 101. Thetop jaw member 306 may also be made of a transparent material that is atleast partly transparent to the light beam 104 to allow the light beam104 to pass through the top jaw member 306 to the eyes of a surgeon. Asa result, the surgeon can view the vascular tissue 101 and the vessels205 grasped between jaw members 306, 307. This enables the surgeon tomore accurately and easily position the jaw members 306, 307 and tocontrol the sealing process and ultimately the quality of the tissueseal.

As shown in FIG. 3, the jaw members 306, 307 make direct contact withthe vascular tissue 101. In some instances, the tissue may adhere to theinside surface of the jaw members 306, 307. To prevent this, the jawmembers 306, 307 may include an optically-transparent coating with lowadhesion to tissue, such as optically-transparent collagen.

The light source 120 may include one or more lasers, e.g., asemiconductor laser or a fiber laser. The spectrum of the laserradiation may contain one or more spectral components that lie withinthe absorption range of the vascular tissue 101. The light guide 110delivers the light 103 generated by the light source 120 to a lightdistribution element 111. The light guide 110 may include an opticalwaveguide such as an optical fiber or a bundle of optical fibers.

The light distribution element 111 receives the light 103 from the lightguide 110 and forms the light 103 into a light beam 104. To form thelight beam 104, the light distribution element 111 may include a prismor an appropriate waveguide structure. The light distribution element111 may also include a spatially periodic optical structure such as anamplitude-phase gratin_(g) or a long-period fiber Bragg grating.

The wavelength of the light 103 emitted from the light source 120 may betuned to vary the diffraction pattern created by the spatially-periodicoptical structure of the light distribution system ill. For example, thewavelength of the light 103 may be tuned to vary the direction ofpropagation of the diffracted light (i.e., the light beam 104) to adjustthe light penetration depth and the amount of light energy transmittedto the vascular tissue 101. In this way, the heating of the vasculartissue 101 may be controlled.

To increase the efficient use of light energy, reflective components maybe used to cause the light beam 104 to pass through the tissue beingsealed multiple times. For example, as shown in FIG. 3, the outersurface of the upper jaw member 306 may include a reflective coating 308and the outer surface of the lower jaw member 307 may include areflective coating 309. In this embodiment, the light beam 104 emittedfrom the spatially periodic optical structure of the light distributionsystem 111 may pass through the vascular tissue 101, reflect off of thereflective coating 308, pass again through the vascular tissue 101,reflect off of the reflective coating 309, pass again through thevascular tissue 101, and so forth. To allow a surgeon to see thevascular tissue 101 through the transparent jaw members 306, 307, thereflective coatings 308, 309 may be made of a spectrally selectivematerial that reflects the light used to seal the vessel (e.g., near IRlight), but transmits visible light.

The jaw members 306, 307 may be made of material with low thermalconductivity because, unlike RF-based sealing methods and instruments,the systems, instruments, and methods according to embodiments of thepresent disclosure do not require electrically conductive electrodes,which typically have high thermal conductivity. When metal electrodeswith high thermal conductivity come into physical contact with vasculartissue, a significant amount of heat is lost through the body of theinstrument. Because the jaw members 306, 307 are not heated by thelight, the jaw member material can be selected to have low adhesion tothe vascular tissue or a transparent lubricant may be applied to theinner surfaces of the jaw members 306, 307 to prevent the vasculartissue 101 from adhering to the jaw members 306, 307.

FIGS. 4 and 5 show cross-sectional side and front views of an instrumentfor sealing vascular tissue. In this embodiment, the jaw members 306,307 deform the vascular tissue 101 by extending or stretching thevascular tissue 101 along the length-wise axis of the vascular tissue101 rather than compressing the vascular tissue 101, to intensify therelease of elastin and collagen. The upper jaw member 306 includes twosides that define a cavity 315 and are shaped to mate with the roundedupper portion of the lower jaw member 307. The lower jaw member 307includes an aperture 320 through which a light beam 104 passes from thelight distribution element 311 to the cavity 315.

As the jaw members 306, 307 are brought together to deform the vascular101, the two sides of the upper jaw member 306 stretch or extend thevascular tissue 101 that is to be illuminated by the light beam 104across the upper portion of the lower jaw member 307 by pulling thesurrounding tissue in opposite directions 203 a, 203 b. Consequently,the different layers of vascular tissue 101 (e.g., the opposite walls ofthe vessel 205 of FIG. 2) are made thinner and are brought into contactwith each other.

The advantage of this embodiment is that there is no direct physicalcontact between the jaw members 306, 307 and that portion of thevascular tissue 101 that is illuminated by the light beam 104. Similarto FIG. 3, the instrument includes a light distribution element 111disposed in the lower jaw member 307 a predetermined distance from thevascular tissue 101. The light distribution element 111 forms a lightbeam 104 and illuminates the vascular tissue 101 through the aperture320. The light distribution element 111 may include optical fibers,lenses, and/or prisms optically coupled to a light source (e.g., thelight source 120 of FIG. 3) via a light guide (e.g., the light guide 110of FIG. 3). The optical fibers may contain a grating structure todistribute the light beam 104 out of the side of the optical fibersalong a predetermined length of the optical fibers.

The propagation direction and the wavelength of the light 104 areselected to provide the desired tissue penetration depth by the lightbeam 104. Since neither the light distribution element 111 nor the jawmembers 306, 307 have direct physical contact with that portion of thetissue that is illuminated by the light beam 104, the sealed vasculartissue never adheres to any portion of the instrument. In. this manner,the jaw members 306, 307 and the light distribution element 111 avoidcontamination by the sealed vascular tissue 101.

FIG. 6 shows a cutting member 600 of an instrument for vascular tissuesealing that includes a waveguide having three layers 601-603, a lightdistribution element 604, and a cutting edge 605. As the cutting edge605 cuts through vascular tissue 101, the light distribution element 604receives light 103, forms a light beam 104, and illuminates the cutsurfaces of the layers of vascular tissue 101 with the light beam 104through the sides of the cutting member 600. Accordingly, the cuttingmember 600 allows a user to simultaneously cut vascular tissue 101 usingthe cutting edge 605 and seal vascular tissue 101 using the light beam104.

As shown in FIG. 6, layers 601, 603 form the walls of the waveguide andlayer 602 is the medium through which the light 103 propagates. Thecutting member's waveguide is optically coupled to the light source 120,which generates the light 103. In some embodiments, the cutting member600 may itself include a light source (e.g., semiconductor lasers) thatgenerates the light 103. The waveguide 601-603 directs the light 103generated by the light source to the light distribution element 604 in adirection 611 parallel to the x-axis 611. The light distribution element604, in turn, directs and distributes the light beam 104 through theside of the cutting edge 605 across the layers of vascular tissue 101that are cut by the cutting edge 605. In this manner, the cutting member600 can more completely and uniformly illuminate the layers of thevascular tissue 101 with the light beam 104.

The light source 120 may generate light 103 having multiple light raysthat impinge on all or a portion of the light distribution element 604.The light distribution element 604, in turn, would form the light 103into a light beam that spans not only the length of the lightdistribution element 604 (i.e., the dimension of the light distributionelement 604 along the x-axis 611), but also at least a portion of theheight of the light distribution element 604 (i.e., the dimension of thelight distribution element 604 along the z-axis 613). For example, thelight source 120 may generate light 103 having multiple light rays thatimpinge on the entire area (i.e., length times width) of the lightdistribution element 604, in which case the light distribution element604 would form a light beam having a cross section defined by the areaof the light distribution element 604.

Alternatively, or in combination with the cutting edge 605, the cuttingmember 600 may use optical energy to cut the tissue 101. For example,the cutting member 600 includes an optical cutting element 610 thatforms the light 103 or light from a separate light source into a lightbeam 615 that can cut the tissue 101.

As also shown in FIG. 6, the light distribution element 604 is a spatialperiodic optical structure such as a grating structure. The spatialperiodic optical structure diffracts the light so that it penetrates thelayers of cut vascular tissue 101 at a predetermined angle. In otherembodiments, instead of a spatial periodic optical structure, the lightdistribution element 604 includes other reflective or refractivematerials configured to redirect and distribute the light 104 across thecut layers of the vascular tissue 101. For example, the reflective orrefractive materials may be configured to create conditions offrustrated total internal reflection at the outer surfaces of thewaveguide's outer layers 601, 603. In this configuration, the light beam104 passes energy from the cutting member 600 across the ambient medium(i.e., air) to the vascular tissue 101 when the outer surfaces of thecutting member 600 are near enough to the vascular tissue 101.

FIG. 7 shows a front cross-sectional view of the cutting member 600 ofFIG. 6 that is incorporated into a surgical instrument having jawmembers 706, 707 for grasping, compressing, and holding the vasculartissue 101. The jaw members 706, 707 include recesses 716, 717 extendingalong the length (i.e., along the x-axis 611) of the jaw members 706,707 to guide the movement of the cutting member 600 along the x-axis611.

At the start of a tissue sealing procedure, the jaw members 706, 707grasp, compress, and hold the vascular tissue 101. While the jaw members706, 707 hold the vascular tissue 101, the cutting member 600 is movedalong the x-axis 611 to cut the vascular tissue 101. At the same time,the light distribution element 604 directs and distributes a light beam104 across the surfaces of the cut vascular tissue 101. As describedabove, the light distribution element 604 may distribute light 103 alongboth a portion of the length of the cutting member 600 as shown in FIG.6 (i.e., along the length of the light distribution element 604) and aportion of the height of the cutting member 600 as shown in FIGS. 6 and7 (i.e., along the height of the light distribution element 604 as shownin FIG. 6). In other words, the light distribution element 604 maydistribute the light 104 so that it illuminates a cross-sectional areaof cut tissue.

FIG. 8 is a flow diagram of a method or process of sealing vasculartissue by scanning the vascular tissue with a light spot according tosome embodiments of the present disclosure. After starting in 801.,vascular tissue is deformed in step 802 so that different layers of thevascular tissue physically contact each other. In step 804, a light spotis formed, and, in step 805, the light spot is scanned over at least oneportion of the vascular tissue. While the light spot is scanned over thevascular tissue, at least one tissue parameter is monitored in step 806.For example, the tissue temperature may be monitored. Then, at least oneparameter of the light spot is controlled 808 based on the at least onetissue parameter monitored in step 806. For example, the intensity ofthe light spot may be varied based on the monitored tissue temperature.Finally, the process ends in step 809.

Although this disclosure has been described with respect to particularembodiments, it will be readily apparent to those having ordinary skillin the art to which it appertains that changes and modifications may bemade thereto without departing from the spirit or scope of thedisclosure. For example, the controller 114 of FIG. 1 may includecircuitry and other hardware, rather than, or in combination with,programmable instructions executed by a microprocessor for processingthe sensed information and determining the control signals to transmitto the power supply 118 and/or the light source 120.

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosures be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of particular embodiments.

1-19. (canceled)
 20. An energy-based instrument for sealing tissue,comprising: an end effector assembly including first and second jawmembers pivotably coupled about a pivot, at least one of the first andsecond jaw members being pivotable relative to the other about the pivotfrom a first position wherein the first and second jaw members aredisposed in spaced relation relative to one another to at least a secondposition wherein the first and second jaw members cooperate to deformtissue; and an optical system configured to illuminate tissue with lightto seal tissue, the optical system comprising: a light source configuredto generate light; a light distribution element configured to distributethe light over tissue; and a light guide configured to guide the lightfrom the light source to the light distribution element, wherein thelight distribution element is disposed in the first jaw member, andwherein the light distribution element is further configured to adjustan incident angle of the light with respect to tissue.
 21. Theenergy-based instrument of claim 20, wherein the light distributionelement adjusts the incident angle with respect to an axis perpendicularto a surface of deformed tissue.
 22. The energy-based instrument ofclaim 20, wherein the light distribution element adjusts the incidentangle to create total internal reflection before tissue is deformed. 23.The energy-based instrument of claim 22, wherein the light distributionelement adjusts the incident angle to create frustrated total internalreflection when tissue is deformed.
 24. The energy-based instrument ofclaim 20, wherein the light includes at least one spectral componentthat is within a range of absorption spectra of tissue.
 25. Theenergy-based instrument of claim 20, wherein the light distributionelement adjusts the incident angle to control a light penetration depth.26. The energy-based instrument of claim 20, further comprising a sensorconfigured to sense at least one parameter of the light.
 27. Theenergy-based instrument of claim 26, wherein the at least one parameterof the light is one or more of intensity, frequency, polarization,phase, pulse width, pulse frequency, duty cycle, repetition rate, waveshape, duration of illumination, total exposure of tissue to the light,or the spectra of the light.
 28. The energy-based instrument of claim20, wherein the light source includes at least one light-emitting diodeor at least one laser.
 29. The energy-based instrument of claim 28,wherein the at least one laser generates light having differentwavelengths.
 30. The energy-based instrument of claim 28, wherein the atleast one laser is a tunable laser that is tuned to generate light of adesired wavelength.
 31. The energy-based instrument of claim 20, whereinthe light distribution element includes at least one lens or at leastone prism.
 32. The energy-based instrument of claim 20, wherein thelight distribution element includes at least one periodic opticalstructure.
 33. The energy-based instrument of claim 32, wherein the atleast one periodic optical structure is a diffraction grating.
 34. Theenergy-based instrument of claim 33, wherein the diffraction grating isa Bragg diffraction grating.
 35. The energy-based instrument of claim20, wherein the light distribution element includes at least onewaveguide structure.
 36. The energy-based instrument of claim 20,wherein at least one of the first and second jaw members is coated withan optically-transparent coating with low adhesion to tissue.
 37. Theenergy-based instrument of claim 36, wherein the optically-transparentcoating is optically-transparent collagen.